基于收缩徐变试验的大跨径PC连续刚构桥长期挠度可靠度分析

Reliability Analysis on Long-term Deflection of Long-span PC Continuous Rigid Frame Bridge Based on Shrinkage and Creep Test

为探究C60低收缩低徐变高性能混凝土收缩徐变效应对连续刚构桥长期挠度可靠度的影响,以某连续刚构桥为工程背景,开展C60低收缩低徐变高性能混凝土收缩徐变试验,基于试验数据拟合得到该混凝土收缩徐变计算公式,并根据《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 3362—2018),将该混凝土收缩徐变计算公式代入已建好的该桥MIDAS模型中,运用RSM-MC方法,分别建立了使用普通C60混凝土和该混凝土条件下的该桥跨中截面挠度功能函数,计算了该桥在设计基准期100年内的跨中截面挠度失效概率。研究结果表明:使用该混凝土相比于普通C60混凝土能有效地减小挠度失效概率,研究成果可为工程应用提供依据。

In order to explore the influence of the shrinkage and creep effect of C60 low shrinkage and low creep high-performance concrete on the long-term deflection reliability of a continuous rigid frame bridge,taking a continuous rigid frame bridge as the engineering background,the shrinkage and creep test of C60 low shrinkage and low creep high-performance concrete is carried out,and the concrete shrinkage and creep calculation formula is obtained based on the test data. According to the Design Code for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts( JTG 3362—2018),the concrete shrinkage and creep calculation formula is substituted into the established MIDAS model of the bridge,and the RSM-MC method is used to respectively establish the deflection function of the midspan section of the bridge under the condition of using ordinary C60concrete and this kind of concrete,and calculate the deflection failure probability of the midspan section of the bridge within 100 years of the design reference period. The research results show that: compared with ordinary C60concrete,this kind of concrete can effectively reduce the deflection failure probability,and the research results can provide basis for the engineering application.